Human Nature
by AnimeDrummer
Summary: Sucky summary, but here goes. Take the Parasyte series and mix in random things, and what do you get? I don't know either, but this story is basically that and then some.
1. Chapter 1

After re-watching a classic animated monster movie after so long for a few times, I finally had a reason to write another Parasyte fic. That, and a guest who reviewed my first Parasyte story said I should do another one. Let's see after a while if you can guess which movie I'm watching again and again just by reading this or by the songs from it I'm attempting to rewrite; one will be sung by Shinichi and one will be sung by Satomi. I'm taking bits and pieces from the movie as well as the Parasyte series in attempt to create a new story. The main characters went through some rough times like confidence/self-esteem issues, a certain girl they like, and even a few changes that affect those around them after getting hurt by or becoming monsters. Note: Shinichi doesn't have glasses, just like in the manga.

Though it felt like just another ordinary night, tiny green spores fell from space, landing everywhere across the globe. Hidden inside these spores were tiny organisms that would change the way people looked at the world. One person in particular was about to be dragged into a predicament beyond his control.

One of the organisms landed just outside a bedroom window. As it leaped, it landed next to the young teen asleep. After the boy sprung awake, it looked like the worm disappeared, but managed to drill into his hand. The boy couldn't help but shout out as he was trying to make heads or tails of what was happening. Next thing he knew, his earphone cords were tangled around his arm.

His parents came in wondering what had happened. Next thing he knew the green light in his skin was gone.

"Shinichi, we thought we heard something, are you all right?" his mom asked.

"I don't know. I thought I saw some glowing snake. And then I thought it burrowed. There was a light climbing up my arm."

"No wonder you look half-asleep, you have your earphones tangled around it. You really should be more careful."

"Hold on, let me take a look. Something about a small hole and a glowing snake?" his dad stepped up.

"It's gone? Doesn't even hurt. Strange..."

"You sure you're getting enough sleep? You look exhausted."

"I guess you're right, this is way too much."

"Good idea."

 **A few hours later...**

A new day was rising. Another ordinary morning for Shinichi Izumi. His room had a shelf filled with all different kinds of books, which was the first thing he eyed. Placing some books in his bag and others on his desk, he was just about ready to start the day. This seemingly ordinary high school teen made his way downstairs. His parents were right there as he began. Breakfast, of course was the same.

"Geez, you still look like crap. You get _any_ sleep last night?"

"Not sure. I just hope my hand's not messed up."

"It's because your earphones were tangled up. Here, have a bit more before you go." his mom said.

"You sure, Mom?"

"Yes, I'm sure. You hardly eat anything in the morning."

After breakfast, he was just about ready to go. But then...

"Shinichi, everything going okay at school?" his dad wondered.

"It's fine, Dad."

"Just that maybe you're hitting the books too much. I'm only making sure you're all right."

"I guess you're right. I did have a lot to do last night. I probably couldn't help but doze off later than usual. I"ll try to be back on time today."

With that, he was on his way. Shinichi knew that it was another ordinary day. The classes were the same, and so were the people. Just then he saw someone up ahead.

"About time, Shinichi."

"Yuko?"

"You sure seem out of it." she said.

"Why's that?"

"Looks like something's wrong with your hand..."

"I've been busy the past few nights, but I should be okay."

Class after class just past by so suddenly. Before he knew it, on the way before he reached the gates, he was stopped by another friend.

"What's the hurry, Shinichi?"

"Oh. Hey, Kamijo."

"I saw Satomi Murano headed your way right now. How awesome is that?" the friend told him.

"She is?" Shinichi seemed surprised.

"Yeah, man. Try talking to her."

A girl about the same age as Shinichi approached. They've known each other since they met before high school, but she had never attempted to get to know the real Shinichi. This would be a good starting point.

"Shinichi." said Satomi.

"Murano, hi." he jumped.

"Don't be so nervous. We haven't talked in a while."

As they talked just while standing there, they went on about their separate classes, as well as rumor about a new teacher. Just then, she noticed the boy was slightly uneasy.

"Shinichi, you're not looking so good. Yuko told me about how you kinda seemed out of it." the girl moved herself closer.

"It's actually nice you're concerned about me, but I've already decided to take off early today."

"Okay then..."

"Feel free to text tonight. It felt nice talking like this." With that, Shinichi slowly walked off.

"OK, I'll try to leave a text tonight." Satomi sounded rather chipper she got to see Shinichi after some time.

(So far, so good.) Kamijo smiled.

 **A while later...**

Shinichi just walked around before he headed back when he nearly walked into a wall without looking ahead. Next thing he knew, there were some things falling and it looked like it would all land on him. Unbeknownst to him, his hand began changing and his fingers replaced by razor blades. Looking up, he saw his hand moving on its own as it sliced the falling objects. Realizing what happened, Shinichi freaked out. How was it possible his hand could do this? Without a second thought, he rushed back to the house. (It was the first thing that came to mind. I know the manga and anime were different in this situation, but I wanted to write something unexpected.)

He finally arrived. Still frantic, he tried not to worry his mom as rushed upstairs. Nobuko slightly caught a glimpse of him as he headed up and wondered.

"Shinichi's home this early? I wonder what's wrong."

Still out of his mind, Shinichi tried to comprehend his current predicament. He goes through his desk drawer and finds an exacto blade.

"Okay, let's see if the same thing happens this time. I know my hand became deformed and it's probably that damn thing from last night."

Just then, his hand began changing again. This time however, a mouth, tiny hands and some eyes appeared instead of what was to be expected. Shinichi looked even more freaked out as he couldn't help but think what was happening.

"Right hand... Most unfortunate..."

"Unfortunate? You can talk? Wait, what are you? What happened to my hand?" he asked.

"I... am your right hand. After replacing it." his hand's new voice spoke.

"Replaced?" Shinichi was very taken by this.

"Your language is still new to me, Shinichi."

"You know my name too? What the hell are you?" he couldn't believe what came to pass.

"Must rest now..."

"None of this makes any sense. I had a few more questions." Shinichi slunk to the floor holding his hand. Trying to process the facts in front of him, he wonders what he got himself into.

At last the first chapter's done. Yes, I'll introduce a few more people in the following chapters, but I'm still not sure if I wanna add Kana. If I do, she can't compete with Satomi for Shinichi, but she can be a good friend. Also, not every parasite from the anime/manga will be in this. Not sure if I'll keep this T or further down the road make it M. I guess it depends. Prepare for a very unusual retelling of one of my top favorites in anime.


	2. Chapter 2

I have some time on my hands so I decided to do this next chapter. Last time, Shinichi went through quite the ordeal, and now wonders why his hand can suddenly talk.

Shinichi felt nearly down and out about what happened. Reducing those falling objects to debris, and realizing his hand was talking to him.

"No way I can tell Mom and Dad about this. They just wouldn't understand."

Then, he heard a sound from his bag.

"A text? Let's see here." He opened it and was surprised by who it was.

 _Shinichi, hope you're doing all right. Think we can talk before school tomorrow? I feel like the time we had today was cut short. Let me know when you get this. l8r_

"A text from Murano. I should probably say something."

 _Thanks for the heads up. And yes, I'm feeling a little better. I'll see if I can message you again in the morning and I'll leave early so we can talk._

Little did most people across the nation realize, that they'd be victimized in a seemingly brutal manner. The news and police are completely baffled. Nighttime came and went. As for Shinichi, he was off on a bit of a slow start.

"Ugh, morning already? It's morning and I'm awake! But why do I feel like I'm still asleep?"

Shinchi looked down at his seemingly unusual hand as his books were scattered across the floor.

"What are you doing?"

"As you can probably see, I'm brushing up on all of your planet's various lifeforms."

"Guess you talk now, so what was that last night? Is that worm thing what you're supposed to look like?"

"I am unsure. Rather unsettling, none of your texts or on-screen information have any details about me. But there some interesting records on small organisms called parasites. Like them, I also seem to rely on the nutrients in your bloodstream for survival."

"Maybe you come here from a distant planet or something?"

"It's strange. The earliest memory is of you and how unfortunate it was to occupy your brain?"

"What the hell do you mean by my brain? And is that next?"

"If so I would have done it already, but I had already matured after eating your hand. Most unfortunate."

"What would've happened then?"

"Not too much. Just you'd look the same, but your head would open in a few different ways."

"That's crazy sick! So, any reason I'm in the middle of all this?"

"A matter of chance seeing as how you weren't specifically chosen."

"Guess I should do that since I'm already up."

"Do what?"

"It's called messaging. This device lets humans communicate with one another from far away. Okay, now I just have to figure out what to say. Ah, got it!"

 _Morning, Murano. Just had a little trouble getting out of bed, but after breakfast, I'll be out the door. See you in front of the school._

"Fascinating."

"Also, when going downstairs for breakfast, try to stay hidden." said Shinichi while re collecting his books.

"Certainly. It would be unsettling for someone to notice your hand was suddenly talking."

The teen finally made his way downstairs with his phone close at hand. His parents were getting situated.

"Mom, are my bacon and eggs ready?" he asked.

"Just about. I'm surprised you remembered." said Nobuko.

"You were the one who said I needed a fuller breakfast. And just one more slice of toast?"

Oh, okay. You sure are hungry this morning."

"Can't believe there were three more attacks last night." the dad seemed surprised.

"You mean the recent murders?" Shinichi wondered.

"Yeah. In this area, a mother and daughter were killed and the father's gone without a trace. A beheading in a nearby province, and there even was a total hackjob where the victims were indescribable."

"Please, Kazuyuki, not this early in the morning." the mom complained.

"Oh, right. What's that?"

"Wait, that's me. Looks like another text." the troubled teen looked down.

 _I'm glad you remembered this morning. It's great that you'll be there today. I'm about to head out myself. I'll be waiting._

"A text? Could it be a girl?" the dad wondered.

"It is."

"You're texting a girl?" Shinichi's mom was very surprised. "Would we know who she was?"

"Doubt it. I should go, I told her I'd get to the school early so we can talk. She's already on her way there."

Shinichi's parents waited til he was gone to say anything.

"Nobuko, did you even know that he was talking to a girl?" Kazuyuki asked.

"I'm as surprised as you are." she answered.

Before he knew it, he was close to the school.

"Now that I think of it, you could probably use a name."

"I don't really see the need for names; I'm neither a person nor your pet."

"I gotta come up with something, I can't just say 'you' all the time. I'm thinking 'Migi'."

"Migi?"

"Makes sense since you took over my right hand."

Satomi realized she got ahead of her so she wanted to surprise him. Before the chop could connect, Shinichi's hand surprisingly caught it.

"Shinichi?"

He turned and noticed her.

"Murano? I thought you were ahead of me."

"Yet somehow you got ahead of me."

"You wanna talk on the way?"

"That's what we said we'd do."

They talked a bit more about their separate classes and how they'd like to message each other when stuff happens. Satomi seemed to notice more confidence in Shinichi's voice as they talked. As they got closer to the school, Migi felt as if something big was going to happen.

"Shinichi..."

"Migi?"

"Down here. I sense one of my kind nearby."

"What there's more of you? How can you tell?" he whispered.

"I can feel it as if it was like brainwaves. We're definitely getting close to it."

"Are you saying it's at the school?"

"It's highly likely."

All the students were gathered into one room. Shinchi nervously looked around.

"It's here, but it seems its looking for us in this large crowd as well. So long as no direct contact is made, we should be safe."

"Welcome, students. I wish introduce our new senior class math teacher filling in for Mr. Matsuyama. I now present Miss Reiko Tamura."

"It's her..."

"And as of today, Mr. Yamamoto will become the new homeroom teacher for Class 3-3. And Miss Tamura will act as assistant homeroom teacher."

"We've been found. Don't look." said Migi. Shinichi couldn't feel anymore nervous.

 **Later...**

Math class was occurring normally, well normally compared to others. But to Shinichi, he still felt rather unsettled.

(How can Migi sleep so calmly at a time like this?)

"Oh, class is through already? Mr. Izumi, do you have a minute? Simply meet me in the teacher's office." said Reiko as she exited.

(Why make her move now?)

"Man, Shinichi. You would think our new teacher's taken an interest in you or something."

"Give it a rest, Taku. Tell him it's not like that." Shinichi replied to his friend a few seats ahead.

"Yeah, especially since I saw you talking to Satomi Murano this morning. Seems you two are awfully close now."

"You really saw us talking, Akiho? This is just great..."

"You can't be serious." Taku turned to her. "Why is it that nervous wreck Shinichi gets by with everything and everyone?"

Shinichi shot up and grabbed Taku out of rage greatly shocking Akiho and even Yuko who was seated next to him. "What's that supposed to mean, you bastard! Just lay off!"

"Shinichi..." Yuko seemed more worried about her friend in this light than anyone. As he released him, Taku fell to the ground.

"Besides, I'm not even sure she'd go out with me... even if I asked." And he was slowly out the door with his head down.

"Shinichi... I was hoping to mentally prepare you for what's about to happen. Surprisingly after taking over the host, she still manages to stay blended into society."

"Migi, what are you trying to say? Shouldn't we try to do something?" Shinichi asked.

"What do you mean?"

"Just think about it. Chances are she's gonna wipe everyone out."

"I doubt that. It seems she wants to blend in. It would be rather unlikely that she'd endanger anyone."

"We can't be too sure."

"Which is why we should observe her from afar for the time being."

The two arrive outside the door. She was just ahead.

"Miss Tamura?"

"Yes, come in."

Shinichi advanced slowly. "I assume you know what I am, Mr. Izumi."

"Then you know about...?"

"The signal from your right hand? Why, yes. It seems we're different from the others."

"Others?"

"The others who are causing the recent deaths that people are calling the Mincemeat Murders."

"So, wait. _Other_ parasites are going around slaughtering people and eating them? That's what we're dealing with?"

"I'm not looking to harm you or anyone. I myself don't see the point in feeding the way other parasites do."

"I feel the same way. I sustain on the nutrients in Shinichi's blood, so I also do not understand our kind's need to resort to cannibalism."

"It would seem that we are among the humans to accomplish something. I'd like your help in figuring out what it is."

"I don't know about this, it seems too unreal."

"Must most of you humans be so irrational? However, this my first time experiencing a case like yours. I've only ever encountered hosts that have been completely taken over. I might need to gather more information. And in time, we can go over a foreseeable future."

"Future?"

Reiko simply walks out. "I'll let you know when we need to meet privately again."

The rest of the day was more relaxing for Shinichi knowing that Reiko had no purpose of hurting anyone. Then, as the final class let out, Shinichi was looking out side a window when all a sudden...

"Shinichi?"

"Murano. Was I supposed to...?"

"No, I just happened to see you out here. I can't stick around so I'll text you later."

"Yeah, I have to go too."

As they parted ways, Migi noticed two things while they were taking the railway.

"I've noticed something very peculiar earlier, Shinichi. Your heart rate becomes slightly elevated around that female."

"You mean Murano?"

"Exactly. It seems you have some sort of interest with her."

"I-interest?"

"Wait, I'm sensing one of my kind. In one of the cars behind us."

"All right." He gets off at the next stop.

"What it this? We are 40 meters away and getting closer."

"I wanna face this guy head on."

"Wouldn't that be foolish?"

"We're the only ones who know what these things are doing to people. I can't stand to let this continue to happen!"

"5 meters."

"Is that him?"

Just then, it was there; spiky hair and a menacing look. (Think back to Episode 2)

"So, you were unable to take the brain of your host. Disappointing. It's far too dangerous letting this human live."

"I will not hesitate if you advance." said Migi.

"There you are. I thought you'd be somewhere. Face it, the only way for you to survive after I kill this pathetic host is align with me!" His blades went straight for Shinichi.

With two horizontal slashes, Migi stood his ground knowing he was going to defend Shinichi at any cost.

"Migi? How did you...?"

"You... I can't believe this...! My body..." Like that, it was over.

"So that's it?" the boy asked.

"Apparently, if our kind our removed from our host, we would surely shrivel and die from malnutrition."

"Guess it's a good thing I didn't have a hospital examine us."

"Yes, very much so. At the the same time, you would lose your right hand in the process; unfortunate for both of us."

"It's as if you knew what would happen. But it was one of your kind."

"I've already decided. I will protect you from any possible threat, Shinichi."

"But now, I can't just walk home with drops of blood on my hand."

They found a place for Shinichi to rinse off the blood before heading back home.

"Shinichi, that's cold."

Okay, everyone. I'm gonna end it here. I know this looks like a big mess, but I assure you, it will get better. Just give it time. If you have any questions about the next few chapters, let me know. Thanks and stick around for what happens next.


End file.
